1. Field of the Invention
The present invention relates to a steering device equipped with a tilt and telescopic adjustment mechanism, and more particularly to a steering device of a structure in which the clamping state during the tilt and telescopic adjustment is reinforced and which excels as a whole in durability.
2. Description of the Related Art
A variety of steering devices equipped with a tilt-telescopic mechanism have been developed. Recently developed devices have a structure in which an outer pipe and an inner column are locked and unlocked with a clamp member during tilt and telescopic adjustment. A device of this kind is disclosed in Japanese Patent Application Publication No. 2006-69524. The device according to Japanese Patent Application Publication No. 2006-69524 is briefly described below. In the explanation below, the reference numerals assigned to the components are those described in Japanese Patent Application Publication No. 2006-69524 and they are included in parentheses to distinguish them from the reference numerals of the present application.
In the steering column device described in Japanese Patent Application Publication No. 2006-69524, a hollow cylindrical outer column (1) is mated with the rear side of an inner column (2), as viewed along the vehicle body (same hereinbelow), so that the outer column can slide in the axial direction. The outer column (1) is attached to a vehicle body (6) with an upper-side vehicle body attachment bracket (3). A slit (14) is formed in the lower surface of the outer column (1). The slit (14) is formed from an end surface (17) on the front side of the outer column (1).
On the front side of the inner column (2), the lower-side vehicle body attachment bracket (7) is attached to the vehicle body (6), and a tilt central shaft (21) fixed to the front side of the inner column (2) is tiltably supported by the lower-side vehicle body attachment bracket (7). A pair of left and right flanges (31A), (31B) for attaching the upper-side vehicle body attachment bracket (3) to the vehicle body (6) is formed in the upper section of the upper-side vehicle body attachment bracket (3).
The flanges (31A), (31B) are formed integrally, and at the inner side surfaces (321A), (321B) of the left and right side plates (32A), (32B) extending in the up-down direction, a clamp member (8) is clamped to allow for telescopic and tilt movement. A circular-arc inner circumferential surface (82) formed at the inner side of the clamp member (8) encircles an outer circumference (11) of the outer column (1). The clamp member (8) is disposed at a position such as to enclose the slit (14) of the upper column (1) from both sides.
A separation location is present at the lower side of the clamp member (8). A slit, which is the separation location of the clamp member (8), is formed along the lower surface side of the clamp member (8) similarly to the slit (14) of the outer column (1). Where the clamp member (8) is clamped, the outer column (1) is reduced in diameter, and the inner column (2) is held.
After the clamp member (8) and the outer column (1) have been unclamped from the upper-side vehicle body attachment bracket (3), a steering wheel (5) is grasped and the outer column (1) and the clamp member (8) are slid in the axial direction with respect to the inner column (2) to adjust to the desired telescopic position. At the same time, they are adjusted to the desired tilt position by rotation about the tilt central shaft (21). Then, the clamp member (8) is clamped to the upper-side vehicle body attachment bracket (3).